Current Status of Thyroid Fine-Needle Aspiration Practice in Thailand

Abstract

Thyroid carcinoma is one of the leading malignancies in Thailand increasingly prevalent in the female population. Fine-needle aspiration (FNA) cytology is a widely used diagnostic tool for evaluation of thyroid nodules and thyroid cancer. Thyroid FNA is a routine procedure universally performed in Thai hospitals by a variety of clinical specialists. Manual guidance is the first-line choice complemented by ultrasound assistance in selected cases. Despite national guidelines recommendations, the diagnostic criteria and terminology of the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) was slowly adopted in the local settings. Currently, the Bethesda system is actively promoted by the local professional societies as a uniform reporting system. Experience with thyroid FNA has been rarely reported to date—only a handful of publications are available in local journals. Our review, in addition to presenting various aspects of thyroid FNA in Thailand, established for the first time national references for a certain statistical outputs of TBSRTC based on the original multi-institutional cohort. The risk of malignancy in 2,017 operated thyroid nodules collected from three tertiary thyroid cancer centers was 21.7%, 14.7%, 35.9%, 44.4%, 76.7%, and 92.6% for categories I to VI, respectively. The malignancy risk in several diagnostic categories (II to IV) was higher than the risk estimated by TBSRTC and recent meta-analysis studies. We endorse the use of uniform terminology of the Bethesda system in Thailand, which will help facilitate communication among diverse medical professionals involved in the management of patients with thyroid nodules, to share local experience with the international audience.

Thyroid FNA cytology in Asian practice—Active surveillance for indeterminate thyroid nodules reduces overtreatment of thyroid carcinomas

“…In addition, there are reports of significant variations in ROM in cytological‐histological correlation studies even when the ATA thyroid cancer management guidelines and the Bethesda system were employed . This article presents high quality data provided by members of the Working Group of Asian Thyroid FNA Cytology, which confirms high ROMs in the indeterminate FNA categories and low rates of non‐invasive follicular neoplasm with papillary‐like nuclear features (NIFTP) in most Asian thyroid FNA practice . This article also provides an overview of Asian thyroid FNAC practice and gives possible reasons for the significant differences between Asian and western practice.…”

“…Keelawat et al provided their thyroid FNA practice data from Chulalongkorn University, Thailand for 2010‐2015 (n=2722) . Proportions of FNA samples for the six Bethesda categories were 47.6% for non‐diagnostic, 40.8% for benign, 3.9% for AUS/FLUS, 2.6% for FN/SFN, 1.9% for SM and 3.2% for malignant, respectively.…”

“…They further provided data from three medical centres in Thailand on resected nodules. Mean ROMs and range for the six Bethesda categories from the three centres were 21.7% (19.2%‐22.6%) for non‐diagnostic, 14.7% (14%‐15.2%) for benign, 35.9% (32.9%‐44.4%) for AUS/FLUS, 44.4% (20.9%‐58.3%) for FN/SFN, 76.7% (70.4%‐81.5%) and 92.6% (91.9%‐93.6%) for malignant, respectively . Their ROM for AUS/FLUS was high, but that for FN/SFN nodules was only slightly high.…”

“…Their ROM for AUS/FLUS was high, but that for FN/SFN nodules was only slightly high. They reported that the Bethesda system is the most widely accepted reporting system but aspirates with cystic fluid only were considered as benign by some readers in Thailand …”

“…There are two types of clinical practice and reporting systems for thyroid FNAC of thyroid nodules in Asian countries. The majority of Asian countries have established their own guidelines for the management of thyroid nodules/cancer and these national guidelines often endorse the use of ATA guidelines and the Bethesda system . Japan, however, has developed its own clinical guidelines for the treatment of thyroid nodules.…”